As part of trying to flog Plaxo to a friend, I went to the Plaxo site, which I hadn't visited for a while to update my Plaxo profile with my GrandCentral info. A couple of days ago I had signed up for an OpenID using Verisign as my OpenID provider.
The Plaxo first-time-OpenID-sign-in process wasn't all that intuitive, requiring first (unannounced as far as I could tell) that my OpenID be "attached" to my Plaxo Id.
The first time I tried associating one with the other, the process flunked. The second time worked, though, as far as I could tell, I did exactly the same steps. If someone wasn't medium sophisticated in this stuff, it's unclear if they would have prevailed.